Urginea maritima bulbs coming into leaf for the winter in mid to late November. The foliage is green throughout the chilly, sometimes even freezing, nights of winter and yellow into dormancy in mid to late April.
Giant white squill (Urginea maritima, syn Drimia maritima) is a fascinating large bulb from the Mediterranean regions of Europe. They activate growth in the fall with the first rains, when large straplike leaves push forth from the cantaloupe-sized, half-buried bulb, and grow all winter and into the spring. They yellow out and die off before extreme summer heat arrives, usually by early May. The bulbs are encased in many layers of brown, papery scales that help prevent summer water loss and reduce temperature stress.
Small offsets are forming at the base of this Urginea. With time and in suitable conditions, these bulbs will divide into sizable clumps containing 6 to as many as 30 bulbs all crowded together.
The most surprising feature of white squill is the sudden late summer appearance of a flower spike, often in the fierce heat of August, in the total absence of all leaves or other outward signs of life. Drawing upon the stored water and energy reserves of the massive bulb, this bottlebrush-like flower spike stands 4 to 7 feet tall, and sports thousands of white, star-shaped flowers. The plants will set seed, scatter it in time for the fall rains, and then go back to dormancy until October or November when the cycle repeats.
White squill bulbs for sale in August 2018. The smaller ones up front are about a pound in weight and the size of a very large amaryllis bulb. The larger ones in the back are 2.5 to 3 pounds each and approximately the size of a cantaloupe melon.
The timing of this type of floral display is common in Mediterranean-type, winter-rainfall climates. Termed hysteranthy, this process of producing flowers and seeds before leaves is thought to have a couple of advantages, ecologically speaking. One is that it helps the seeds deal with the unpredictability of rainfall in these types of climates, which can be very wet some years and very dry in others. By being produced regardless of how good the wet season is, the seeds can remain dormant in the soil until rainfall is adequate to inspire germination and survival.
Closer-up view of the bulbs showing the interesting and somewhat colorful reddish-brown to purplish papery sheaths.
Another benefit is that there tends to be little else in bloom at the time of year when the white squill flowers, which reduces competition for the pollination services of insects, which will focus instead upon the squill for lack of having any other options. And since seeds are broadcast in late summer and fall, when seed predator populations (birds, rodents, insects) are lower than in spring, the odds of seedling survival are increased as well. Hysteranthy is also found in a number of other species, including garden favorites such as amaryllis and saffron crocuses.
By late August 2018 several of the rootless, unplanted Urginea bulbs had started to produce flower spikes, so I potted them up into 2-gallon sized pots and started watering them so that they could root and grow.
When I first learned about these unique and dramatically large bulbs, I knew I had to have some. I found a source online, where 5 bulbs could be had for $125. Not cheap, but worth the cost for plant nuts like me. The ones I was buying had apparently been field-grown in the Imperial Valley east of San Diego, and were tolerant of the extreme heat and aridity of the lower desert there. Each bulb weighed 2.5 to 3 lbs and was supposedly capable of tolerating outright desert conditions. So I put them to the test.
The first flowers on the first potted spike are opening, which proceeds from the base upwards to the tip over about two weeks total.
This was back in 2004, and the bulbs have been successfully growing for me every year since then, through wet winters and dry ones, without fail. Although I watered them during dry spells for the first several years, I have not helped them out at all in at least 10 years as of 2018, and they survive and grow on my 8 inches (20 cm) of annual precipitation without my help. This fact alone makes me love them all the more. In any case the cool leaves add visual punch to the landscape, resembling nothing else in my desert xeriscape.
Regarding cold tolerance of the foliage which is green and actively growing during the coldest months of the year: The leaves are easily able to tolerate freezing to about 20 to 22 F (-5 to -6 C) with little or no damage. However I lost the leaves to very hard frosts a couple of times in 2007 and 2011 when temperatures dropped to about 13 to 15 degrees F (-10 to -11 C). Fortunately they grew more greenery out of the bulb, like grass would, although they didn’t look normal for the rest of the season. They did grow as normal the following seasons, but the stress of leaf loss and replacement probably cost them the ability to flower the next summer.
Wild specimens of Urginea maritima in habitat in Turkey, April 2, 2018. The natural range of this bulb is almost entirely around the Mediterranean Basin, including France, Italy, Greece, Turkey, Lebanon, Israel, Cyprus, Crete, Malta, Libya, Algeria, and Morocco. They adapt well to any other Mediterranean climate, and as I am showing, even to the southeastern Mojave Desert and Sonoran Desert in the USA.
One thing I noticed about the bulbs is that they have large, thick, and fleshy roots that run pretty deep. I suspect that these roots are permanent and do not fully die back every summer, given their size and diameter. It’s probably important to the plant to preserve these roots since it might take a lot of energy for the plant to replace them. So if I were to move a non-dormant leafy bulb, I would take pains to get a good length of the roots (and a soil ball if possible) and not twist or break them. That might help with quicker recovery. Of course transplanting once established should be avoided unless absolutely necessary, since root trauma will set the plants back for at least one growing season and inhibit flowering. That said, they are tough and long-lived, so if sacrificing a single year’s blooming in favor of obtaining one for your garden is required, then go ahead and do it because they will be worth the long-term investment.
Bees are attracted to the flowers early in the morning. I was hoping for some cross-pollination between different flower spikes being open at the same time, but I think that bees stole the entire pollen crop and the florets never developed into seed pods. I have seen this happen with agaves that should be fertile too. In summer, there is little else here for bees to consume, so they aggressively collect every pollen grain they can find. By mid-morning the bees are largely gone, because there is neither pollen nor nectar left in the flowers.
Even better, nothing wants to eat this plant! It is reportedly highly toxic and is sometimes used in a chopped-up form mixed with edible bait to kill rats, mice, and other pests. I have had nothing try to eat either the flower spikes or the leaves, no matter how little else there is to consume. Being poisonous works for many plants, clearly, or else they wouldn’t do it.
This carpenter bee (Xylocopa sp) is also attracted to the only game in town. But since these large bees are usually not active until midday, the nonnative feral honeybees (mainly Africanized now in my region) have taken all of the pollen and nectar well beforehand since they are usually swarming the flowers just as it is getting light outside, well before sunrise. This competition for limited resources by invasive bees has taken a measurable toll on numerous other native bee populations in the Southwest.
I have not seen any flower spikes in several years, but this is probably my own fault for not watering them extra anymore. I don’t think the bulbs can store enough energy to flower the next summer on my relatively minimal winter rainfall. After all, Mediterranean climates are not truly desert ones, and they do get more rain and with greater reliability. If I were to help them out I presume that I could get them blooming again. Now that I live here full-time, I may be able to be more reliable with watering. But there’s no question that this is a suitable, hardy bulb for warm desert regions. I heartily recommend them.
Sunrise floods the desert with the light of a new day on Sept 9, 2018.
The photo above was taken about a week after the earlier ones were, and the bulbs are about half bloomed-out by now. The spikes lasted about another week before fading. Leaves on these and other bulbs that I potted that didn’t bloom are emerging now, in late November 2018, which is a bit behind ground-bedded bulbs. But the potted ones were delayed in leafing out due to the need to develop roots, which the planted ones don’t need to do, so their foliage usually emerges by early November.
Happy growing!
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Addendum from January 30, 2019: This was originally posted on Facebook and I simply copied the text I wrote there over to this blog entry since it added another dimension to the discussion of these interesting bulbs.
Some hefty roots pushing out of the base of a white squill bulb, one of the ones shown rootless in August 2018 in the post above.
Look at the roots emerging on this thing! This is a large bulb of Urginea maritima (Drimia maritima) that I potted a few months ago back in October. It started sprouting the leaf cone by early November, but leaf development stalled out at about this level since the plant had not yet formed any roots. The coiled bunch of leaves could do some photosynthesis, but the bulb was unable to risk fully unfurling them because that could lead to dehydration and depleted energy reserves if the bulbs had no way to absorb water. Despite getting a vegetative head start, for full growth they need their roots as well.
No wonder that a mass of these roots all emerging at once will have a tendency to lift the bulbs out of the soil, rather than diving down into it. Upon replanting at the correct depth the roots of course stay put and rooted down into the pot as they are supposed to. It just took an extra try. 🙂
Finally, in the past few weeks, I have noticed many of the Urgineas starting to rise up in their pots, as the force of a mass of thick, white roots actually lifted the bulb upwards rather than penetrating into the soil. As I saw this, I tried to gently press the bulbs back into the soil and firm more dirt around them so the roots would go down and not push the bulb up. But this individual was perched up high, as if it were on stilts. So I took it out of the pot, photographed it, and then replanted it at the correct depth.
This photo shows the root anatomy of many large, long-lived bulbous plants, including Urginea, Amaryllis, and Lilium. In species such as these, which live for years or even decades and have large showy flowers and significant foliage, the normally hidden root system must support them through a variety of weather factors, including in many places long droughts. The thick, fleshy roots are probably perennial and never completely die off, and when mature can run for two or more meters through the soil. These heavy roots represent significant biomass and confer a survival advantage to the bulbs by serving as repositories of water and stored energy, in addition to that which is also stored in the bulbs themselves. Ordinarily unseen, I thought these photos showed this thick-rooted trait in an interesting way. 🌷
My giant squill (Urginea maritima) is doing great, Jan! It has leaves about 3 inches tall coming up now. Mine gets less sun this time of year and I was afraid it would not develop its leaves. I am so happy! I just don’t understand why more people in Arizona don’t grow these bulbs. They are SO spectacular! Thank you for introducing them to me!
It will probably develop earlier next year – this was the first season and it needs to still form more roots. My established plants leafed out at the beginning of November, but my newly planted ones waited until around Thanksgiving to start. It won’t be as late in future years.
I have not watered mine either. Would watering some in June, July, August in Phoenix be advantageous for blooming?
It probably won’t encourage any blooming if the plant isn’t already primed to do it because the flower buds develop the previous growing season and are already formed in miniature inside the bulb by springtime dormancy, so that they are ready to pop out come summertime. However if it does decide to bloom, and there hasn’t been any monsoon rain, some watering certainly won’t hurt them and might well help sustain the show. Mine get rainfall only in July and August, unless flowering, in which case I help some with a weekly or so watering. But they probably would survive without that even.
Thanks for the info, Jan. I will water as you do. We will see what happens next year! Love watching it grow!
I Live in inland San Diego area and planted my first Urginea bulb 12 years ago. I now have a large clump I would like to divide next year. The bloom spike appears every year in week 3-4 in August. How many weeks prior to this should I plan to pull out of the ground? Also, can they send up 2 flower spikes on 1 bulb?
The bulb clumps are probably best divided in early summer, just after the leaves go dormant for the warm season. This probably means May or June in San Diego County. Remember that the roots are perennial and thick and fleshy, so you may want to dig some distance away from the clump and lift a bunch of soil with it, and then set that on the ground and gently pry bulbs off sideways trying not to tear too many roots loose, although it is virtually inevitable that some root damage will occur.
The bulbs are fairly tough and resilient so if you take some care then any damaged roots will likely be replaced come late summer and early fall when rain hopefully starts to return. I would do minimal watering over the summer during post-division dormancy, maybe just once or twice to settle the roots in and then mostly dry the rest of the summer. In September you can start watering and eventually they should push new leaves, and roots as well which of course you won’t be able to see.
Digging and dividing may well sacrifice flowers for a year, although I have had bulbs flower from a completely dormant uprooted state anyway, just in much reduced form. You may not suffer flowering loss, but if you do then that’s to be expected that first year. But they will likely resume normal growth and blooming again in year 2 and beyond. I think that getting two flower spikes out of one bulb is pretty rare, but I doubt it’s completely impossible. If it does happen it would probably be either simultaneous or closely successive, meaning one spike shows up and then a second appears only a week later, likely being a bit smaller. I’ve not had it happen on mine – but I don’t think it’s out of the question, either.
I moved my one bulb that had become three. They did have a huge root system for a bulb, much larger than I expected, most of which got cut off by the shovel. They did not produce foliage the following winter and appeared dead, but all three came back last winter and bloomed this past summer, and they have a fine set of leaves this winter, so they recovered from the traumatic loss of root system. Have never gotten more than two or three seeds, Bees taking all the pollen, I guess.
Interesting, thanks for the report. They are pretty tough survivors, although they do take a long time to recover once stressed and transplanted.
Is it possible to grow them in the pot, cause my location in the northern part of the NY state ?
They grow fine in pots, but the problem is that they are winter growing and summer dormant. So in NY they would try to have leaves at the coldest time of year with the shortest days, which probably means the plants won’t have as much capacity to photosynthesize since they need to be indoors because winter in NY is too cold. Indoor light is always lower in intensity than outdoor light, and in winter even more so. So the plant will never produce enough energy to bloom and all you’ll get is leaves, which to be fair are interesting enough in their own right I suppose. Plus it has a summer dormancy like I said, so you would have to look at a leafless pot with nothing more than the upper third to half of the bulb showing for 6 months of the year. It’s honestly not the best choice for a potted plant in cold winter climates, but it’s probably possible.
Hi, my giant squill has been in the ground from past 3-4 years but has not flowered so far. Itis now about 1.5 lb weight. The problem is that in winter when the leaves open, it gets shaded partly by surrounding trees. Should I moveit or should I wait? Thanks.
You do not mention where you live, so I cannot be sure of what your climate is, but it sounds like you have the plant in the ground as opposed to a pot, which indicates somewhere in California or Arizona, or perhaps southern Nevada even. Plants in the desert regions of all those states are significantly less likely to flower than ones in coastal California, which very closely resembles their native Mediterranean climate. They do survive deserts but they are not as ideally adapted to them as the milder coastal regions.
I for instance grow a dozen or so Urginea maritima bulbs here in the desert of northwestern Arizona, and I have only gotten a handful of flower spikes over the past 15 years from the plants. As I just said they survive the deserts just fine for years on end, but even in full sun I have found blooming in the extreme heat of August or early September to be an improbable event, sadly. If you also live in an interior desert location, it might simply be the climate being less conductive to flowering than a milder, less hot locale along the ocean is.
If however you do live in coastal California (meaning even as much as 50 or 100 miles inland, but not in the eastern or southeastern California Mojave or Sonoran Deserts per se) and you have no flowering then it is indeed possible that shade in the winter cool growing season is hampering photosynthesis enough to discourage flowering in the summers. They do manufacture food in the form of sugars and starches in the winters, which are stored for flowering fuel usage the next summer, so fairly full sun is best for this. That said, if the bulbs do receive a minimum of 6 or 7 hours of winter sun daily, then a bit of partial shading won’t really interfere with the process.
You’ll have to assess your situation based upon these guidelines. If you happen to live somewhere else entirely and I have not addressed your climate or state correctly, then my advice might differ. In any case if you do think that too much shade is stopping adequate photosynthesis to build a surplus of bulb energy in the short days of winter and early spring, then you can indeed consider relocating the bulbs and seeing if that helps. The best time to transplant is probably the late summer or early fall, just before the bulbs break dormancy in October. As for myself, I have accepted that blooming Urginea maritima is a rare event for my garden and I enjoy it when it happens, but I am willing to grow the bulbs for their foliage alone in the meantime. The leaves add an interesting element to a winter and spring desert garden independent of any flowering they may do in summer heat.
By the way 1.5 lbs is a sizable bulb but not as large as they can attain at maturity (2-3 lbs each, and clumps can have several large bulbs after 6 to 10 years of growth) so the lack of flowering may also simply be related to immaturity and not be dependent upon growth conditions for the time being. Again, without knowing where you live or what your garden conditions in particular are, I can only offer general things to consider. I hope this helps.
Hi, my giant squill is 3-4 year old and weighs 1.5 lb approx but has never bloomed here is zone 9b San Jose. The problem is that it gets part shade from surrounding trees in winter. should I wait longer for it or should I move it?
This comment went to the spam folder via the automated filtration system so I didn’t see it for a few days, and by the time I did I had already answered your other comment. See that for a better reply.
Hi- Just purchased my first Urginea maritima Giant Sea Squill bulb. I live in Atlanta (zone 7B) I’m assuming it’s best to plant in the ground, not to keep it potted (for the reasons discussed in previous comments) Is it best to plant in succulent/cactus soil? If there is a major temperature drop in the Winter, can I cover the plant? Is it the freezing temps or the moisture that will hurt it? (meaning, should I wrap it in a blanket or perhaps build a water-blocking enclosure around it? Thank you!
I don’t think that you will be easily able to plant this particular bulb species into the ground in Atlanta. While they do tolerate some cold and wet over the winter months since that is when they receive rainfall in the Mediterranean regions they are native to, facing temperatures much below 23 to 25 F will likely kill back much of the foliage. While they can regrow that foliage at least once a year (since I’ve seen them do it here in AZ winters after facing temps in the low 20s on occasion) it might happen too often in Atlanta for them to survive. You can cover the foliage with heavy covers during such cold snaps, but it’s a pain in the butt to remember to do it.
Of equal if not greater concern however are the hot and humid Georgia summers, which are when the bulbs are dormant. In their native Mediterranean climates, summer rainfall is more or less nonexistent and humidity is low, which helps enforce dormancy and prevents rotting. But since Georgia sees abundant rainfall more or less year-round, the bulbs will face wetness at a time of year when they are normally warm and dry (including in the AZ desert where I live, once again) and this could lead to rotting on either the thick perennial roots, or the bulbs themselves, which can obviously be deadly. Therefore even if you do winter cold protection, I think that avoidance of excessive summer moisture while dormant is equally important if not more so.
I would suggest planting the bulb(s) in a large pot which you can migrate around somewhat readily to avoid both those winter nights and those summer rains. Using a sizable pot that allows room for the roots will probably work just fine and I’ve grown potted plants for sale in relatively smallish pots for several years, and they live just fine. I don’t do them in bigger pots because of sales purposes, but for a permanent situation you can easily succeed by upsizing the pot a bit. Using a well drained soil mix suitable for cacti and succulents is best indeed.
Once in a pot you can keep them in good conditions both in leafy growth in winter (i.e. chilly, but not frigid, and damp is okay), and summer dormancy (i.e. warm and dry) by moving them into a garage or under a porch, sheltered from rainfall. Offering a splash of water once every month in summer won’t be fatal and will help maintain root health, just don’t let them get soaked repeatedly and stay wet all summer long. Normal dormancy is between early May and mid October or so. If they do decide to bloom, it will probably be between mid August and mid September, and they can do so even if kept more or less completely dry, although if I note flowering emergence then I water some to help support that. After all, AZ is a lot hotter and drier than the Mediterranean regions so I modify the watering schedule a bit to reflect that should they flower in the worst of late summer AZ heat.
You can of course always try planting into the ground to see if it works for them to survive hot and humid summers without protection during dormancy. They might tolerate it better than I think. I just don’t have data on it and am surmising based upon their natural habitat and how they do in somewhat similar climates. After all, I wasn’t expecting these bulbs to survive on only an average of 8 inches of rainfall a year without aid (some years are even less) but they have for almost 17 years now done just that. They never bloom, because they don’t have the strength, but they don’t die either and the leaves come back every year. Ones in better conditions in the garden zones where I water more regularly do bloom more reliably. And sometimes we see significant summer monsoonal rain in July-Sept, and that doesn’t seem to hurt them in dormancy either, but of course AZ is much drier than GA is on average. So if you want to try and experiment then I’d like to know your findings over time. They are not difficult bulbs to grow in most regards and they do exhibit a range of tolerance that might extend to the SE USA.
SO helpful, Jan. Thank you!!
Hi, these bulbs are not white squill, the belong to the red squill Urginea (syn. Drimia) numidica, occurring wild from Morocco to Cyprus, Southern Italy and mainland Greece along with some, if not all, Aegean islands. It can grow together with a white-bulbed squill, Urginea pancration. The true maritima is restricted to the Iberian peninsula and north-western Morocco, at least from Rabat to Ceuta (a small territory ruled by Spain).
I tried looking up the several species you mentioned and I’m not coming up with clear differences between them, at least not with limited online image searching which may often not be of the species you are seeking. I do not know the wild origins of the bulbs since they were grown in captivity in the USA anyway, so they may indeed well be one of the other species you mentioned.
I am looking for one of these bulbs but can’t find any… Anyone interested in trading for naked ladies or Clivias or… I am in San Francisco. CA
I have two small/medium sized bulbs in pots available. They have not broken dormancy yet and I assume they are still alive. They’d be $20 each. You can email me at jan @ dfranch com if you want to discuss it. I wish I had more but I sold them all a couple of years back other than these two.